Biomedical Engineering Advancements after Management of Myelomeningocele Study (MOMS): A Narrative Review

Spina bifida is a neural tube defect resulting from an incomplete closure of the caudal neuropore. The most debilitating form of spina bifida, myelomeningocele (MMC), can present with Chiari II malformation with concomitant hydrocephalus, bowel and bladder abnormalities, and impaired motor function of the lower limbs. The incidence rate of spina bifida is 3.4 per 10,000 live births reported within the US. On average, the US spends $1,176,000,000 annually on patient management and treatment. Advancements in the standard therapy, namely prenatal intervention pioneered by the Management of Myelomeningocele Study (MOMS), have aimed to reduce maternal and fetal complications, and yet complications were increased, calling for the need of further improvements. Beyond current standard interventions for MMC, the most promising developments have employed various biomedical methods ranging from isolated stem cell injections to biodegradable scaffold patches. These scaffolds can be biologic or synthetic and are often incorporated with bioactive proteins or stem cells. This review discusses the benefits and limitations of post-MOMS era biomedical engineering intervention articles found in 3 medical and biomedical databases consisting of systematic reviews, meta-analyses, randomized control trials, and experimental studies. After analysis of the advancements and limitations of these studies, a combination of materials could create a superior scaffold possessing watertight impermeability and cytocompatibility for successful coverage and host integration with minimal inflammation. Coupled with minimally invasive intra-amniotic injection delivery, an earlier mitigation could further prevent progression of poor neurologic outcomes, and possibly even regenerate neuronal tissue in patients with MMC

Development of Standard Criteria to Evaluate the Effectiveness of Helmets at Decreasing the Risk of Concussions

In many sports, such as American football, accumulations of mild traumatic brain injuries have been suggested as a possible link to neurodegeneration and future mental disorders. With head impacts occurring at all levels of competition and in different sports, it is critical to develop an accurate method for quantifying the effects of head impacts and determining the efficacy of helmets. This study examines the derivation of different dimensionless numbers and ascertains the critical factors needed to predict the effects of head impacts, specifically the resulting accelerations from an impact. Given a known force of impact, parameters such as peak translation acceleration and impact duration were collected for a total of 200 impacts at 10 locations around the head. These parameters were used in conjunction with dimensionless numbers to compare various helmet designs across sports. Five input and four output criteria, or π variables, were derived using fundamental variables of total mass, width of neck, and the difference between muscle reaction time and the impact duration. By determining the coefficients of the governing equations for each output π variable, the impulse of impacts had a consistent effect on helmet efficacy, while the masses and radii of helmets contained confounding variables that made it difficult to predict the effectiveness of attenuating the head accelerations

In-vivo evaluation of biocompatibility of biodegradable Fe-Mn materials

The authors evaluated the biodegradability and biocompatibility of an alloy of iron and manganese in a bone model in vivo. Fe-Mn biodegradable materials with various porosities were first fabricated and characterized for microstructure, corrosion and mechanical properties. Resorption of a bioabsorbable wire of chemical formula Fe30Mn and no induced porosity was evaluated in-vivo. The Fe-Mn alloy behavior in-vivo was compared to that of a traditional permanent 316L stainless steel (SS) wire after bilateral transcondylar femoral implantation in 12 rats. Evaluation of biodegradation was performed over a period of 6 months using serial radiography, post-mortem histology and macroscopic implant surface analysis. Increased bone ingrowth was noted at the iron-manganese wire-bone interface, which indicates increased osseointegration of the implant. Please click Additional Files below to see the full abstract

In vivo articular cartilage deformation: noninvasive quantification of intratissue strain during joint contact in the human knee

The in vivo measurement of articular cartilage deformation is essential to understand how mechanical forces distribute throughout the healthy tissue and change over time in the pathologic joint. Displacements or strain may serve as a functional imaging biomarker for healthy, diseased, and repaired tissues, but unfortunately intratissue cartilage deformation in vivo is largely unknown. Here, we directly quantified for the first time deformation patterns through the thickness of tibiofemoral articular cartilage in healthy human volunteers. Magnetic resonance imaging acquisitions were synchronized with physiologically relevant compressive loading and used to visualize and measure regional displacement and strain of tibiofemoral articular cartilage in a sagittal plane. We found that compression (of 1/2 body weight) applied at the foot produced a sliding, rigid-body displacement at the tibiofemoral cartilage interface, that loading generated subject- and gender-specific and regionally complex patterns of intratissue strains, and that dominant cartilage strains (approaching 12%) were in shear. Maximum principle and shear strain measures in the tibia were correlated with body mass index. Our MRI-based approach may accelerate the development of regenerative therapies for diseased or damaged cartilage, which is currently limited by the lack of reliable in vivo methods for noninvasive assessment of functional changes following treatment

Comparative Analysis of Impact Attenuation Properties from Soccer Headgear

Athletes suffering from long-term neurocognitive deficiency due to subconcussive impacts is a major concern for football and soccer players today. Football players wear helmets that can help reduce injury risks like skull fractures, and these helmets must meet standard criteria that determinines how well a functional helmet should reduce accelerations of the player’s head. Currently no standard exists for testing soccer headgear despite studies demonstrating soccer players experience similar magnitudes of impacts. In this study, a modal impact hammer was used in conjunction with a Hybrid III 50th percentile test dummy head to simulate impacts experienced by soccer players to quantify the effectiveness of headgear in attenuating head acceleration due to direct impacts. The study found one device to be functional, and able to reduce the translational acceleration for an average hit experienced by a soccer player by 20%. Devices need to be developed and common testing standards need to be established to allow for a more widespread implementation of similar devices to protect players from short and long-term injuries due to impacts

Finite deformation elastography of articular cartilage and biomaterials based on imaging and topology optimization

Tissues and engineered biomaterials exhibit exquisite local variation in stiffness that defines their function. Conventional elastography quantifies stiffness in soft (e.g. brain, liver) tissue, but robust quantification in stiff (e.g. musculoskeletal) tissues is challenging due to dissipation of high frequency shear waves. We describe new development of finite deformation elastography that utilizes magnetic resonance imaging of low frequency, physiological-level (large magnitude) displacements, coupled to an iterative topology optimization routine to investigate stiffness heterogeneity, including spatial gradients and inclusions. We reconstruct 2D and 3D stiffness distributions in bilayer agarose hydrogels and silicon materials that exhibit heterogeneous displacement/strain responses. We map stiffness in porcine and sheep articular cartilage deep within the bony articular joint space in situ for the first time. Elevated cartilage stiffness localized to the superficial zone is further related to collagen fiber compaction and loss of water content during cyclic loading, as assessed by independent T2 measurements. We additionally describe technical challenges needed to achieve in vivo elastography measurements. Our results introduce new functional imaging biomarkers, which can be assessed nondestructively, with clinical potential to diagnose and track progression of disease in early stages, including osteoarthritis or tissue degeneration. </div

Methods and Compositions Based on Culturing Microorganisms in Low Sedimental Fluid Shear Conditions

The benefits of applying a low sedimental fluid shear environment to manipulate microorganisms were examined. Microorganisms obtained from a low sedimental fluid shear culture, which exhibit modified phenotypic and molecular genetic characteristics, are useful for the development of novel and improved diagnostics, therapeutics, vaccines, and bio-industrial products. Furthermore, application of low sedimental fluid conditions to microorganisms permits identification of molecules uniquely expressed under these conditions, providing a basis for the design of new therapeutic targets